Prognostic Impact of BRAF and KRAS Mutation in Patients with Colorectal and Appendiceal Peritoneal Metastases Scheduled for CRS and HIPEC

Expert consensus on the optimal management of BRAFV600E-mutant metastatic colorectal cancer in the Asia-Pacific region

The burden of colorectal cancer (CRC) is high in the Asia-Pacific region, and several countries in this region have among the highest and/or fastest growing rates of CRC in the world. A significant proportion of patients will present with or develop metastatic CRC (mCRC), and BRAFV600E-mutant mCRC represents a particularly aggressive phenotype that is less responsive to standard chemotherapies. In light of recent therapeutic advances, an Asia-Pacific expert consensus panel was convened to develop evidence-based recommendations for the diagnosis, treatment, and management of patients with BRAFV600E-mutant mCRC. The expert panel comprised nine medical oncologists from Australia, Hong Kong, Singapore, and Taiwan (the authors), who met to review current literature and develop eight consensus statements that describe the optimal management of BRAFV600E-mutant mCRC in the Asia-Pacific region. As agreed by the expert panel, the consensus statements recommend molecular testing at diagnosis to guide individualized treatment decisions, propose optimal treatment pathways according to microsatellite stability status, advocate for more frequent monitoring of BRAFV600E-mutant mCRC, and discuss local treatment strategies for oligometastatic disease. Together, these expert consensus statements are intended to optimize treatment and improve outcomes for patients with BRAFV600E-mutant mCRC in the Asia-Pacific region.

Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for colorectal peritoneal metastases: A pragmatic comparison of oncological outcomes in synchronous versus metachronous disease

BACKGROUND

disease burden (PCI), completeness of cytoreduction or histological features, are known to influence survival after CRS-HIPEC for colorectal peritoneal metastases (CPM). However, there is still debate about influence of CPM onset. The aim of this study is to determine the impact of CPM onset on oncological outcomes after CRS-HIPEC.

METHODS

all patients with CPM scheduled for CRS-HIPEC at one reference center between December 2007 and September 2022 were included. s-PM were defined as those diagnosed at primary disease treatment; m-PM were considered those diagnosed during follow-up. Survival outcomes and recurrence rates were compared using a pragmatic analysis.

RESULTS

125 patients with s-CPM and 170 patients with m-CPM were analyzed. Median follow-up was 58.6 and 50.6 months in s-CPM and m-CPM groups(p = 0.11). Complete cytoreduction (CCS-0/-1) rates were comparable: 84 % s-CPM vs. 88.2 % m-CPM(p = 0.190). Overall survival (OS) was significantly shorter in s-CPM: 24.7 vs. 46.6 months (p = 0.024). Conversely, median disease-free survival was similar in both groups, 10 months vs. 11 months(p = 0.155). Patients in the s-CPM group presented more pN+(p = 0.001), higher histologic grade(p = 0.007) and PCI(p = 0.04), and higher rate of concurrent liver metastases(p = 0.004). RAS/BRAF gene mutations and microsatellite instability did not differ significantly. Perioperative chemotherapy regimens and tolerance were also similar.

CONCLUSIONS

despite s-CPM being associated with impaired OS after CRS-HIPEC, the onset of PM was not found to be an independent determinant for survival. High-risk molecular and histological features strongly influence oncological outcomes after CRS-HIPEC. This is valuable data that could aid in preoperative patient selection process for CRS-HIPEC.

INDEPSO-ISPSM Consensus on Peritoneal Malignancies: Management of Colorectal Peritoneal Metastases

PURPOSE

This manuscript reports the results of the Indian Network for Development of Peritoneal Surface Oncology and Indian Society of Peritoneal Surface Malignancies (INDEPSO-ISPSM) consensus that aimed to provide recommendations for some important aspects management of patients with colorectal peritoneal metastases (CPM) and address some issues unique to India.

METHODS

The modified Delphi technique was used with two rounds of voting. There were 29 questions on nine main topics-the role of cytoreductive surgery (CRS), patient selection for CRS, preoperative workup, role of systemic chemotherapy (SC), CPM with other visceral metastases, molecular profile, hyperthermic intraperitoneal chemotherapy (HIPEC) and other modalities of intraperitoneal chemotherapy (IPC), prophylactic/preventive strategies, and surveillances after CRS. A consensus was achieved if anyone option received >70 votes (strong consensus >90%).

RESULTS

Forty-eight surgical (n = 41) and gastrointestinal (n = 7) oncologists were invited; 44 agreed to participate. The response rate was 95.4% (42/44) in round 1 and 93.1% (41/44) in round 2. Overall, a consensus was achieved on 23/29 (79.3%) questions (strong consensus on 6/29 [20.6%]). The panel strongly recommended considering surgery for limited CPM with limited liver metastases (92.5%), not altering the surgical approach in patients with KRAS mutations (91.67%), and limiting the use of IPC for unresectable CPM outside clinical trials (95%). Adjuvant SC was recommended for all patients undergoing CRS (89.47%). CRS is a therapeutic option for selected patients with CPM including those with metachronous CPM (79.49) and signet ring cell cancers (76.92%). HIPEC was recommended outside clinical trials only for patients with peritoneal cancer index 11-15(80%).

CONCLUSION

The panel recommended CRS for most indications but was very selective in recommending HIPEC and IPC outside clinical trials. These recommendations should be a useful resource in clinical decision making for clinicians treating CPM in India and regions with a similar sociodemographic background.

Genetic Clustering of Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy Patients of Colorectal Origin: KRAS and Not TP53 Cluster Alterations are Associated with Poor Outcomes

BACKGROUND

The prognostic impact of genetic mutations for patients who undergo cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) of colorectal origin (CRC) is not well defined.

OBJECTIVE

We aimed to describe the genetic classifications in an unsupervised fashion, and the outcomes of this patient population.

METHODS

A retrospective, bi-institutional study was performed on patients who underwent CRS-HIPEC with targeted mutation data with a median follow-up time of 61 months. Functional link analysis was performed using STRING v11.5. Genes with similar functional significance were clustered using unsupervised k-means clustering. Chi-square, Kaplan-Meier, and the log-rank test were used for comparative statistics.

RESULTS

Sixty-four patients with peritoneal carcinomatosis from CRC origin underwent CRS-HIPEC between 2007 and 2022 and genetic mutation data were extracted. We identified 19 unique altered genes, with KRAS (56%), TP53 (33%), and APC (22%) being the most commonly altered; 12.5% had co-altered KRAS/TP53. After creating an interactome map, k-means clustering revealed three functional clusters. Reactome Pathway analysis on three clusters showed unique pathways (1): Ras/FGFR3 signaling; (2) p53 signaling; and (3): NOTCH signaling. Seventy-one percent of patients in cluster 1 had KRAS mutations and a median overall survival of 52.3 months (p < 0.05).

CONCLUSIONS

Patients with peritoneal carcinomatosis (PC) of CRC origin who underwent CRS-HIPEC and with tumors that harbored mutations in cluster 1 (Ras/FGFR3 signaling) had worse outcomes. Pathway disruption and a cluster-centric perspective may affect prognosis more than individual genetic alterations in patients with PC of CRC origin.

Prognostic value of specific KRAS mutations in patients with colorectal peritoneal metastases

BACKGROUND

There is little evidence on KRAS mutational profiles in colorectal cancer (CRC) peritoneal metastases (PM). This study aims to determine the prevalence of specific KRAS mutations and their prognostic value in a homogeneous cohort of patients with isolated CRC PM treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy.

MATERIALS AND METHODS

Data were collected from 13 Italian centers, gathered in a collaborative group of the Italian Society of Surgical Oncology. KRAS mutation subtypes have been correlated with clinical and pathological characteristics and survival [overall survival (OS), local (peritoneal) disease-free survival (LDFS) and disease-free survival (DFS)].

RESULTS

KRAS mutations occurred in 172 patients (47.5%) out of the 362 analyzed. Two different prognostic groups of KRAS mutation subtypes were identified: KRASMUT1 (G12R, G13A, G13C, G13V, Q61H, K117N, A146V), median OS > 120 months and KRASMUT2 (G12A, G12C, G12D, G12S, G12V, G13D, A59E, A59V, A146T), OS: 31.2 months. KRASMUT2 mutations mainly occurred in the P-loop region (P < 0.001) with decreased guanosine triphosphate (GTP) hydrolysis activity (P < 0.001) and were more frequently related to size (P < 0.001) and polarity change (P < 0.001) of the substituted amino acid (AA). When KRASMUT1 and KRASMUT2 were combined with other known prognostic factors (peritoneal cancer index, completeness of cytoreduction score, grading, signet ring cell, N status) in multivariate analysis, KRASMUT1 showed a similar survival rate to KRASWT patients, whereas KRASMUT2 was independently associated with poorer prognosis (hazard ratios: OS 2.1, P < 0.001; DFS 1.9, P < 0.001; LDFS 2.5, P < 0.0001).

CONCLUSIONS

In patients with CRC PM, different KRAS mutation subgroups can be determined according to specific codon substitution, with some mutations (KRASMUT1) that could have a similar prognosis to wild-type patients. These findings should be further investigated in larger series.

Effectiveness of Standard Treatment for Stage 4 Colorectal Cancer: Traditional Management with Surgery, Radiation, and Chemotherapy

Colorectal cancer (CRC) is the second most common cause of cancer-related death in the United States comprising 7.9% of all new cancer diagnoses and 8.6% of all cancer deaths. The combined 5-year relative survival rate for all stages is 65.1% but in its most aggressive form, stage 4 CRC has a 5-year relative survival rate of just 15.1%. For most with stage 4 CRC, treatment is palliative not curative, with the goal to prolong overall survival and maintain an acceptable quality of life. The identification of unique cancer genomic and biologic markers allows patient-specific treatment options. Treatment of stage 4 CRC consists of systemic therapy with chemotherapeutic agents, surgical resection if feasible, potentially including resection of metastasis, palliative radiation in select settings, and targeted therapy toward growth factors. Despite advances in surgical and medical management, metastatic CRC remains a challenging clinical problem associated with poor prognosis and low overall survival.

Genomic Characterization and Clinical Outcomes of Patients with Peritoneal Metastases from the AACR GENIE Biopharma Collaborative Colorectal Cancer Registry

Peritoneal metastases (PM) are common in metastatic colorectal cancer (mCRC). We aimed to characterize patients with mCRC and PM from a clinical and molecular perspective using the American Association of Cancer Research Genomics Evidence Neoplasia Information Exchange (GENIE) Biopharma Collaborative (BPC) registry. Patients' tumor samples underwent targeted next-generation sequencing. Clinical characteristics and treatment outcomes were collected retrospectively. Overall survival (OS) from advanced disease and progression-free survival (PFS) from start of cancer-directed drug regimen were estimated and adjusted for the left truncation bias. A total of 1,281 patients were analyzed, 244 (19%) had PM at time of advanced disease. PM were associated with female sex [OR: 1.67; 95% confidence interval (CI): 1.11-2.54; P = 0.014] and higher histologic grade (OR: 1.72; 95% CI: 1.08-2.71; P = 0.022), while rectal primary tumors were less frequent in patients with PM (OR: 0.51; 95% CI: 0.29-0.88; P < 0.001). APC occurred less frequently in patients with PM (N = 151, 64% vs. N = 788, 79%) while MED12 alterations occurred more frequently in patients with PM (N = 20, 10% vs. N = 32, 4%); differences in MED12 were not significant when restricting to oncogenic and likely oncogenic variants according to OncoKB. Patients with PM had worse OS (HR: 1.45; 95% CI: 1.16-1.81) after adjustment for independently significant clinical and genomic predictors. PFS from initiation of first-line treatment did not differ by presence of PM. In conclusion, PM were more frequent in females and right-sided primary tumors. Differences in frequencies of MED12 and APC alterations were identified between patients with and without PM. PM were associated with shorter OS but not with PFS from first-line treatment.

SIGNIFICANCE

Utilizing the GENIE BPC registry, this study found that PM in patients with colorectal cancer occur more frequently in females and right-sided primary tumors and are associated with worse OS. In addition, we found a lower frequency of APC alterations and a higher frequency in MED12 alterations in patients with PM.

Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy for Peritoneal Metastases from Colorectal Cancer-An Overview of Current Status and Future Perspectives

Peritoneal metastases (PM) are observed in approximately 8% of patients diagnosed with colorectal cancer, either synchronously or metachronously during follow-up. PM often manifests as the sole site of metastasis. PM is associated with a poor prognosis and typically shows resistance to systemic chemotherapy. Consequently, there has been a search for alternative treatment strategies. This review focuses on the global evolution of the combined approach involving cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) for the management of PM. It encompasses accepted clinical guidelines, principles for patient selection, surgical and physiological considerations, biomarkers, pharmacological protocols, and treatment outcomes. Additionally, it integrates the relevant literature and findings from previous studies. The role of CRS and HIPEC, in conjunction with other therapies such as neoadjuvant and adjuvant chemotherapy, is discussed, along with the management of patients presenting with oligometastatic disease. Furthermore, potential avenues for future development in this field are explored.

Recommendations for the optimal management of peritoneal metastases in patients with colorectal cancer: a TTD and GECOP-SEOQ expert consensus statement

Peritoneal metastases (PM) occur when cancer cells spread inside the abdominal cavity and entail an advanced stage of colorectal cancer (CRC). Prognosis, which is poor, correlates highly with tumour burden, as measured by the peritoneal cancer index (PCI). Cytoreductive surgery (CRS) in specialized centres should be offered especially to patients with a low to moderate PCI when complete resection is expected. The presence of resectable metastatic disease in other organs is not a contraindication in well-selected patients. Although several retrospective and small prospective studies have suggested a survival benefit of adding hyperthermic intraperitoneal chemotherapy (HIPEC) to CRS, the recently published phase III studies PRODIGE-7 in CRC patients with PM, and COLOPEC and PROPHYLOCHIP in resected CRC with high-risk of PM, failed to show any survival advantage of this strategy using oxaliplatin in a 30-min perfusion. Final results from ongoing randomized phase III trials testing CRS plus HIPEC based on mitomycin C (MMC) are awaited with interest. In this article, a group of experts selected by the Spanish Group for the Treatment of Digestive Tumours (TTD) and the Spanish Group of Peritoneal Oncologic Surgery (GECOP), which is part of the Spanish Society of Surgical Oncology (SEOQ), reviewed the role of HIPEC plus CRS in CRC patients with PM. As a result, a series of recommendations to optimize the management of these patients is proposed.

Peritoneal Metastasis: A Dilemma and Challenge in the Treatment of Metastatic Colorectal Cancer

Peritoneal metastasis (PM) is a common mode of distant metastasis in colorectal cancer (CRC) and has a poorer prognosis compared to other metastatic sites. The formation of PM foci depends on the synergistic effect of multiple molecules and the modulation of various components of the tumor microenvironment. The current treatment of CRC-PM is based on systemic chemotherapy. However, recent developments in local therapeutic modalities, such as cytoreductive surgery (CRS) and intraperitoneal chemotherapy (IPC), have improved the survival of these patients. This article reviews the research progress on the mechanism, characteristics, diagnosis, and treatment strategies of CRC-PM, and discusses the current challenges, so as to deepen the understanding of CRC-PM among clinicians.

Impact of Molecular Status on Cytoreductive Surgery for Peritoneal Metastases from Colorectal Cancer

Colorectal cancer peritoneal metastases (CRC-PM) are present in 5 to 15% of instances of CRC, and the overall survival (OS) of patients with CRC-PM is much lower than that of patients with other isolated metastatic locations. In recent years, the introduction of cytoreductive surgery (CRS) in conjunction with hyperthermic intraperitoneal chemotherapy has resulted in a significant improvement in CRC-PM patients' OS. Despite this, a significant proportion of CRS patients continue to suffer complications of grades III to V or even die during the perioperative period. Early diagnosis, optimization of patient selection criteria, and refining of individualized combination therapy are necessary for these patients. In this review, we evaluate studies examining the relationship between molecular status and CRS in CRC-PM. Our objective is to gain a comprehensive understanding of how the altered molecular status of CRC-PM impacts CRS, which could increase the likelihood of tailored therapy in the future.

Effect of BRAF mutation on the prognosis for patients with colorectal cancer undergoing cytoreductive surgery for synchronous peritoneal metastasis

Background

KRAS/BRAF mutations (mutKRAS/mutBRAF) are unfavorable prognostic factors for colorectal cancer (CRC) metastases to the liver and lungs. However, their effects on the prognosis for patients with synchronous peritoneal metastasis (S-PM) of CRC after cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) are controversial. In the study, we aimed to determine the effects of mutKRAS/mutBRAF on the prognosis for patients with S-PM who received CRS.

Methods

A total of 142 patients diagnosed with S-PM between July 2007 and July 2019 were included in this study. The demographics, mutKRAS/mutBRAF status, overall survival (OS), and progression-free survival (PFS) of the patients were evaluated. The Kaplan-Meier method and log-rank test were used to estimate the difference in survival between groups.

Results

Among 142 patients, 68 (47.9%) showed mutKRAS and 42 (29.5%) showed mutBRAF. The median OS values were 8.4 and 34.3 months for patients with mutBRAF and BRAF wild-type, respectively (P < 0.01). However, KRAS status was not significantly associated with median OS (P = 0.76). Multivariate analysis revealed carcinoembryonic antigen, CRS, HIPEC, and mutBRAF as independent predictors for OS. Based on these findings, a nomogram was constructed. The C-index was 0.789 (95% confidence interval, 0.742-0.836), indicating good predictive ability of the model. Furthermore, the 1- and 2-year survival calibration plots showed good agreement between the predicted and actual OS rates. The area under curves of the 1- and 2-year survival predictions based on the nomogram were 0.807 and 0.682, respectively. Additionally, mutBRAF was significantly associated with lower PFS (P < 0.001).

Conclusions

mutBRAF is an independent prognostic risk factor for S-PM. The established nomogram predicted the OS of patients with CRC having S-PM with high accuracy, indicating its usefulness as a valuable prognostic tool for the designated patient cohort.

Predictive Genetic Biomarkers for the Development of Peritoneal Metastases in Colorectal Cancer

Metastatic colorectal cancer (CRC) is a common cause of cancer-related mortality, of which peritoneal metastases (PMs) have the worse outcome. Metastasis-specific markers may help predict the spread of tumor cells and select patients for preventive strategies. This exploratory pilot study aimed to gain more insight into genetic alterations in primary CRC tumors, which might be a predictive factor for the development of PM. Forty patients with T3 stage CRC were retrospectively divided in three groups: without metachronous metastases during 5-year follow-up (M0, n = 20), with metachronous liver metastases (LM, n = 10) and with metachronous PM (PM, n = 10). Patients with synchronous metastases were excluded. Primary formalin-fixed paraffin-embedded tumor samples were analyzed via comprehensive genome sequencing (TSO500 analysis) to identify DNA alterations and RNA fusion transcripts in 523 genes and 55 genes, respectively. Thirty-eight samples were included for final analysis. Four M0 tumors and one PM tumor were microsatellite instable. BRAF mutations were uniquely identified in three microsatellite-stable (MSS) PM tumors (37.5%, p = 0.010). RNA analysis showed an additional FAM198A-RAF1 fusion in one PM sample. BRAF p.V600E mutations were only present in PM patients with MSS tumors. Greater attention should be paid to BRAF-mutated tumors in relation to the development of metachronous PM.

The molecular biology of peritoneal metastatic disease

Peritoneal metastases are a common form of tumor cell dissemination in gastrointestinal malignancies. Peritoneal metastatic disease (PMD) is associated with severe morbidity and resistance to currently employed therapies. Given the distinct route of dissemination compared with distant organ metastases, and the unique microenvironment of the peritoneal cavity, specific tumor cell characteristics are needed for the development of PMD. In this review, we provide an overview of the known histopathological, genomic, and transcriptomic features of PMD. We find that cancers representing the mesenchymal subtype are strongly associated with PMD in various malignancies. Furthermore, we discuss the peritoneal niche in which the metastatic cancer cells reside, including the critical role of the peritoneal immune system. Altogether, we show that PMD should be regarded as a distinct disease entity, that requires tailored treatment strategies.

Survival Outcomes of Optimally Treated Colorectal Metastases: The Importance of R0 Status in Surgical Treatment of Hepatic and Peritoneal Surface Disease

BACKGROUND

Although colorectal hepatic metastases (HM) and peritoneal surface disease (PSD) are distinct biologic diseases, they may have similar long-term survival when optimally treated with surgery.

METHODS

This study retrospectively reviewed prospectively managed databases. Patients undergoing R0 or R1 resections were analyzed with descriptive statistics, the Kaplan-Meier method, and Cox regression. Survival was compared over time for the following periods: 1993-2006, 2007-2012, and 2013-2020.

RESULTS

The study enrolled 783 HM patients undergoing liver resection and 204 PSD patients undergoing cytoreduction and hyperthermic intraperitoneal chemotherapy (HIPEC). Compared with PSD patients, HM patients more often had R0 resections (90.3% vs. 32.4%), less often had pre-procedure chemotherapy (52.4% vs. 92.1%), and less often were functionally independent (79.7% vs. 95.6%). The 5-year overall survival for HM was 40.9%, with a median survival period of 45.8 months versus 25.8% and 33.4 months, respectively, for PSD (p < 0.05). When stratified by resection status, R0 HM and R0 PSD did not differ significantly in median survival (49.0 vs. 45.4 months; p = 0.83). The median survival after R1 resection also was similar between HM and PSD (32.6 vs. 26.9 months; p = 0.59). Survival between the two groups again was similar over time when stratified by resection status. The predictors of survival for HM patients were R0 resection, number of lesions, intraoperative transfusion, age, and adjuvant chemotherapy. For the PSD patients, the predictors were peritoneal cancer index (PCI) score, estimated blood loss (EBL), and female gender.

CONCLUSION

The study showed that R0 resections are associated with improved outcomes and that median survival is similar between HM and PSD patients when it is achieved. Surveillance and treatment strategies that facilitate R0 resections are needed to improve results, particularly for PSD.

DNA and RNA Alterations Associated with Colorectal Peritoneal Metastases: A Systematic Review

BACKGROUND

As colorectal cancer (CRC) patients with peritoneal metastases (PM) have a poor prognosis, new treatment options are currently being investigated for CRC patients. Specific biomarkers in the primary tumor could serve as a prediction tool to estimate the risk of distant metastatic spread. This would help identify patients eligible for early treatment.

AIM

To give an overview of previously studied DNA and RNA alterations in the primary tumor correlated to colorectal PM and investigate which gene mutations should be further studied.

METHODS

A systematic review of all published studies reporting genomic analyses on the primary tissue of CRC tumors in relation to PM was undertaken according to PRISMA guidelines.

RESULTS

Overall, 32 studies with 18,906 patients were included. BRAF mutations were analyzed in 17 articles, of which 10 found a significant association with PM. For all other reported genes, no association with PM was found. Two analyses with broader cancer panels did not reveal any new biomarkers.

CONCLUSION

An association of specific biomarkers in the primary tumors of CRC patients with metastatic spread into peritoneum could not be proven. The role of BRAF mutations should be further investigated. In addition, studies searching for potential novel biomarkers are still required.

RAS Mutation Status Should Not Be Used to Predict Outcome from Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy for Colorectal Peritoneal Metastases

BACKGROUND

Genetic biomarkers guide systemic anti-cancer treatment (SACT) in metastatic colorectal cancer. It has been suggested they have a role in selecting patients with colorectal peritoneal metastases (CRPM) for cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC). This study aims to quantify the effect of mutation status on overall survival (OS), adjusting for confounders such as pre-operative systemic anticancer treatment (SACT).

PATIENTS AND METHODS

Retrospective analysis of patients undergoing CRS/HIPEC for CRPM at a national peritoneal tumour centre (2004-2017) was performed. Demographics, treatment history and operative data were extracted. Known biomarker gene mutation status was noted including: KRAS, NRAS, BRAF, PIK3CA and MMR. Cox regression analysis and Kaplan-Meier curves were used to determine overall survival.

RESULTS

One hundred ninety-five patients were included. Median follow-up time was 34.7 months (range 5.4-184.9 months) and median OS was 38.7 months (95% CI 32.4-44.9 months). Biomarker status was as follows: KRAS (n = 114), NRAS (n = 85), BRAF (n = 44), PIK3CA (n = 15) and MMR (n = 21). Mutation rates were 45.6%, 3.5%, 13.6%, 13.3% and 14.3%, respectively. Seventy-four per cent underwent complete cytoreduction (CC = 0), 81% received SACT pre-CRS/HIPEC and 65% post-CRS/HIPEC. RAS (p = 0.21) or BRAF (p = 0.109) mutation status did not predict OS. Nodal involvement, extramural vascular invasion, Peritoneal Cancer Index (PCI) score, CC score, SACT post-HIPEC and NRAS mutation were significant negative predictors of OS in univariate analysis (p < 0.05). Multivariate Cox regression confirmed CC-score > 1 (HR: 7.599, 95% CI 3.402-16.974, p < 0.0001) as a negative predictor of OS. RAS mutation status did not affect outcome (HR: 1.682, 95% CI 0.995-2.843, p = 0.052).

CONCLUSIONS

RAS mutation status should not in isolation be used to select patients for CRS/HIPEC.

Molecular Analyses in Peritoneal Metastasis from Colorectal Cancer: A Review-An English Version

Despite a trend showing continued improvement in survival by combing targeted agents in colorectal cancer, the improvement was limited, and clinically meaningful benefits were not achieved in peritoneal metastasis. The role of cytoreductive surgery (CRS) and proportion of the benefit from hyperthermic intraperitoneal chemotherapy (HIPEC) have been questioned. The PRODIGE 7 study aimed to assess the specific contribution of HIPEC to the survival benefit of peritoneal metastasis from colorectal cancer (CRC-PM) by grouping CRS alone versus CRS with oxaliplatin-based HIPEC, but failed to show any survival improvement. Of these criticisms, oxaliplatin resistance was suggested as the main cause of the negative result. In this regard, the relative resistance to oxaliplatin in consensus molecular subtype 4 colorectal cancer (CRC) is of great interest. Recent treatments for metastatic CRC have gradually moved to precision medicine based on individual biological information through high-throughput technology such as next generation sequencing. This review aimed to provide an overview of the current status of studies reporting the molecular knowledge of CRC-PM.

The prognostic impact of lead times in colorectal cancer patients undergoing cytoreductive surgery and HIPEC

Background

National lead time goals have been implemented across Sweden to standardize and improve cancer patient care. However, the prognostic impact of lead times has not yet been studied in patients with colorectal cancer and peritoneal metastases scheduled for cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS + HIPEC).

Aim

To study the correlation between lead times and overall survival and operability.

Methods

One hundred forty-eight patients with peritoneal metastases originating from colorectal cancer and scheduled for CRS + HIPEC from June 2012 to December 2019 were identified using a HIPEC register at Uppsala University Hospital. Data were collected from medical records concerning operability, overall survival, recurrence and time from diagnosis, and decision to operate to the date of surgery. Patients who had neoadjuvant therapy or no malignant cells in the resected specimens were excluded. Statistical calculations were made with the chi-squared test, Cox regression analysis, and log-rank test.

Results

The median age was 66 years (27–82). Ninety-five were women and 53 were men. One hundred six underwent CRS + HIPEC, 13 CRS only, and 29 were inoperable (open-close). No difference in overall survival was seen when comparing patients with lead times ≤ 34 days and ≥ 35 days from the decision to operate at the multidisciplinary conference to the surgery but there was a higher frequency of open-close (p = 0.023) in the group with longer lead time. Factors that impacted overall survival were open-close (p < 0.001), liver metastases (p = 0.003), and peritoneal cancer index score ≥ 20 (p < 0.001).

Conclusion

A long lead time from multidisciplinary conference to surgery has no direct impact on overall survival but can result in more cases of inoperability. In a larger cohort, this might translate into decreased survival, and efforts should therefore be made to complete preoperative work up as soon as possible and reduce overall time span. Important factors for survival are related to patient selection and extent of disease.

Molecular analyses of peritoneal metastasis from colorectal cancer

Background: Despite a trend showing continued improvement in survival by combing targeted agents for colorectal cancer (CRC), the improvement observed is limited. Moreover, clinically relevant benefits were not achieved in peritoneal metastasis cases. The role of cytoreductive surgery (CRS) and the benefits of hyperthermic intraperitoneal chemotherapy (HIPEC) have been questioned. This review aimed to provide an overview of the current status of the studies reporting on the molecular knowledge of peritoneal metastasis from CRC (CRC-PM).Current Concepts: The PRODIGE 7 study was performed to assess the specific contributions of HIPEC to the survival benefit in CRC-PM cases by comparing CRS treatment alone and CRS with oxaliplatin-based HIPEC. However, this study did not reveal any survival improvement, and oxaliplatin resistance was suggested as the main cause of this negative outcome. Hence, the relative resistance to oxaliplatin in consensus molecular subtype (CMS) 4 CRC is of great interest.Discussion and Conclusion: Recent treatments for metastatic CRC have gradually moved to precision medicine based on individual biological information through high-throughput technology, such as next-generation sequencing. In the transcriptome study, CRC-PM was identified as an almost homogeneous CMS4 classification, which is known to have strong resistance to oxaliplatin-based chemotherapy. These results suggest the need to clarify complex sub-signal transmission pathways derived from transcriptome or proteome studies of CRC-PM. Finally, to compare two studies, it is necessary to establish a representative patient group and consider standardized sample collection, treatment, and analysis.

The impact of molecular and mismatch repair status on the survival outcomes of surgically treated patients with colorectal peritoneal metastases

BACKGROUND

Stratification of patients with colorectal peritoneal metastases (CRPM) using RAS/BRAF mutational status may refine patient selection for cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). This study aimed to analyse the association of RAS/BRAF status and their variants, with clinicopathological variables and survival outcomes in patients who have undergone CRS ± HIPEC.

METHODS

A single centre, peritonectomy database was interrogated for patients with CRPM who underwent peritonectomy procedures between 2010 and 2020.

RESULTS

During the study period, 174 patients were included. Molecular status was obtained on 169 patients, with 68 (40.5%) KRAS, 25 (14.8%) BRAF and 6 (3.6%) NRAS mutations detected. Patients with BRAF mutations were more likely to be mismatch repair deficient (dMMR) (BRAF 20%, KRAS 4.4%, wild type 8.6%, p = 0.015). Most common BRAF and KRAS variants were, V600E (80%) and G12D (39.7%), respectively. BRAF V600E was independently associated with worse overall (median: 28 months, multivariate: HR 2.29, p = 0.026) and disease-free survival (median: 8 months, multivariate: HR 1.8, p = 0.047). KRAS G12V was a strong prognostic factor associated with disease-free survival (median: 9 months, HR 2.63, p = 0.016). dMMR patients (14/161, 8.7%) exhibited worse median overall survival compared to those with proficient MMR (dMMR 27 months, pMMR 29 months p = 0.025).

CONCLUSION

This study highlights the importance of molecular analysis in CRPM stratification. BRAF V600E mutations predict poor outcomes post CRS and HIPEC and may help refine patient selection for this procedure. Molecular analysis should be performed preoperatively to characterise prognosis and guide perioperative therapeutic options.

Impact of KRAS, BRAF and microsatellite instability status after cytoreductive surgery and HIPEC in a national cohort of colorectal peritoneal metastasis patients

BACKGROUND

Patients with metastatic colorectal cancer (mCRC) carrying BRAF (mutBRAF) or KRAS mutation (mutKRAS) have an inferior prognosis after liver or lung surgery, whereas the prognostic role in the context of peritoneal metastasis (PM) after cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) has been less investigated.

METHODS

In total, 257 patients with non-appendiceal PM-CRC were included from the Norwegian National Unit for CRS-HIPEC.

RESULTS

In total, 180 patients received CRS-HIPEC with Mitomycin C, 77 patients received palliative surgery only. In the CRS-HIPEC group, mutBRAF was found in 24.7%, mutKRAS 33.9% and double wild-type 41.4% without differences in survival. MSI was found in 29.3% of mutBRAF cases. Patients with mutBRAF/MSI had superior 5-year survival compared to mutBRAF with MSS (58.3% vs 25.2%, P = 0.022), and better 3-year disease-free survival (DFS) compared to mutKRAS (48.6% vs 17.2%, P = 0.049). Peritoneal Cancer Index and the number of lymph node metastasis were prognostic for OS, and the same two, location and gender prognostic for DFS in multivariate analysis.

CONCLUSIONS

PM-CRC with CRS-HIPEC patients has a surprisingly high proportion of mutBRAF (24.7%). Survival was similar comparing mutBRAF, mutKRAS and double wild-type cases, whereas a small subgroup with mutBRAF and MSI had better survival. Patients with mutBRAF tumours and limited PM should be considered for CRS-HIPEC.

Differences in the distribution of peritoneal metastases in right- versus left-sided colon cancer on MRI

PURPOSE

Right-sided colon tumors with peritoneal metastases (PM) are associated with a poorer prognosis than left-sided tumors. We hypothesized that a different pattern of spread could be characterized with abdominopelvic MRI. The objective of this study was to explore the spread of PM in relation to the primary tumor location on MRI.

METHODS

This is a retrospective cohort study of patients with PM from colon cancer referred to be considered for CRS-HIPEC at a single tertiary referral center. Patients with colon cancer were eligible if they had undergone an abdominopelvic MRI scan following a clinical diagnosis of PM. The frequency of affected PCI regions on MRI (MRI-PCI) was assessed and compared between tumor sidedness.

RESULTS

One hundred eighteen patients were included with a median age of 65 (IQR: 56-72). 46% percent were male. The median MRI-PCI was 10 (IQR: 5-16) and 8 (IQR: 4-11) for right- and left-sided tumors, respectively (p = 0.39), and the median number of affected regions was 4 (IQR: 2-7 for right-sided and IQR 2-5 for left-sided tumors). PM was most frequently found close to the primary tumor. The odds ratio of patients with PM of left sided to be affected with PM in the upper abdominal regions was 0.42 (95% CI: 0.20-0.90) and with PM on the small bowels or mesentery was 0.42 (95% CI: 0.19-0.92) over a patient with PM of right-sided colon cancer.

CONCLUSION

MRI can help to assess the spread of PM in colonic cancer. In right-sided tumors, the small bowel and upper abdominal regions are more frequently affected.

Limitations of laparoscopy to assess the peritoneal cancer index and eligibility for cytoreductive surgery with HIPEC in peritoneal metastasis

PURPOSE

We aimed to determine the value of laparoscopy to assess the intra-abdominal tumor extent and predict complete cytoreduction.

METHODS

All patients at our department in the period from 2017 to 2021 that underwent laparoscopy to assess peritoneal metastasis and subsequent open exploration with the intention to perform cytoreductive surgery (CRS) with HIPEC were retrospectively identified in a continuously maintained database.

RESULTS

Forty-three patients were analyzed. Peritoneal cancer index (PCI) determination by laparoscopy compared to open surgery was overestimated in five patients (11.6%), identical in eleven patients (25.6%), and underestimated in 27 patients (62.8%). PCI differences were independent of surgeons, tumor entities, and prior chemotherapy. Thirty-four patients (79.1%) were determined eligible for CRS with HIPEC during open exploration, whereas nine patients (20.9%) underwent a non-therapeutic laparotomy. Complete or almost complete cytoreduction was achieved in 33 patients (76.7%). In one patient, completeness of cytoreduction was not documented.

CONCLUSIONS

We demonstrate a moderate agreement according to weighted Cohen's kappa analysis of PCI values calculated during laparoscopy and subsequent open exploration for CRS with HIPEC. Uncertainty of PCI assessment should therefore be kept in mind when performing laparoscopy in patients with peritoneal metastasis.

The many faces of intraperitoneal chemotherapy

Cytoreductive surgery and intraperitoneal chemotherapy may offer chance for cure for patients with peritoneal metastasis. Many variations emerged, causing uncertainty when choosing the most suitable variant. By reviewing variability encountered in the management of peritoneal metastasis, we aim to raise awareness about this issue and hopefully initiate efforts to solve it. We review variance encountered in all aspects of this complex field of surgical oncology, indications, patient selection criteria, definition and extent of cytoreductive surgery and the numerous variables of intraperitoneal chemotherapy. Best benefit was achieved with pseudomyxoma peritonei, and to lesser extent in colorectal, ovarian and gastric cancer, but Indications keep expanding to include other tumors pathologies. Selection of patients depends on numerous prognostic indicators and criteria, according to tumor extent and pathology. The standard definition of cytoreductive surgery remains the same, but the boundaries of resection expand. Numerous chemotherapy regimens and administration methods are used, in search for best possible benefit. This variance must be reduced, to make the best use of, and further spread this treatment combination. Practical simple guidelines are needed for surgical oncologists willing to utilize this treatment for their patients, to be considered a true standard of care.

Signet ring cell carcinoma of the gastrointestinal tract: National trends on treatment effects and prognostic outcomes

BACKGROUND

Signet ring cell carcinoma (SRCC) is a distinct malignancy occurring across the tubular gastrointestinal tract (tGIT). We comprehensively examined the outcomes of patients diagnosed with SRCC across tGIT.

METHODS

SRCC and not-otherwise-specified adenocarcinoma (NOS) patients reported to the National Cancer Database from 2004 to 2015 were included. Baseline characteristics, outcomes and site-specific adjusted hazard ratios (aHR) derived from Cox models of SRCC patients were compared to those of NOS patients. Overall survival (OS) was primary endpoint.

RESULTS

A total of 41,686 SRCC (4.6%) and 871,373 NOS patients (95.4%) were included. SRCC patients were younger (63.1 ± 14.7 vs. 67.0 ± 13.4 y, p < 0.001) and more likely to present with Stage IV disease than NOS patients (42.5% vs. 24.5%, p < 0.001). Stomach (n = 24,433) and colon (n = 9,914) contributed highest frequency of SRCC. SRCC histology was associated with shorter OS (aHR = 1.377, p < 0.001) in multivariate model. There was an interaction between SRCC and chemotherapy effects on risk of death (interaction aHR = 1.072, p_interaction< 0.001) and between SRCC histology and disease site, suggesting that the effect of SRCC on OS is site-dependent, with a higher increased risk of death in patients with rectal SRCC (aHR = 2.378, p_interaction< 0.001).

CONCLUSION

Significant negative prognostic effect associated with SRCC is site-dependent across the GIT. Surgical and or systemic therapy was associated with improved OS among SRCC patients, but remained lower than NOS patients. Further understanding of gastrointestinal SRCC molecular profile is needed to better inform future treatment strategies.

Determination of whether HIPEC is beneficial in patients with synchronous peritoneal and liver metastases from colorectal cancer (Review)

Peritoneal carcinomatosis, as well as the presence of liver metastases from colorectal cancer, has been long considered as the sign of a systemic disease, transforming the patient into a candidate for palliation and best supportive care. However, in recent decades, progress in the field of medical and surgical oncology has allowed scientists worldwide to produce curative therapeutic strategies for these cases such as hyperthermic intraperitoneal chemotherapy (HIPEC) or extended liver resection. In addition, the association of these two therapies has also been performed with encouraging results. The aim of the current study was to review articles published thus far in regard to the association of these two therapeutic strategies, in order to identify which cases can benefit the most, which is the most efficient agent or combination of agents, and whether these types of therapy should be performed as monotherapy or as a two-stage procedure.

Clinical and Molecular Features in Patients Undergoing Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy for Peritoneal Carcinosis from Colorectal Cancer

PURPOSE

Careful patient selection plays a crucial role in avoiding overtreatment and further increases survival rates in patients undergoing cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) for colorectal cancer (CRC) with peritoneal metastases (PM).

METHODS

The clinical and molecular factors influencing survival in patients who had undergone CRS with HIPEC between January 2015 and December 2018 were analyzed.

RESULTS

Sixty-six patients underwent CRS with HIPEC during the study period. The median overall survival (OS) was 36 months, with a 3-year OS of 43%. Multivariate analysis revealed increased PCI (HR: 1.21; 95% CI: 1.02-1.41; p = 0.020), right-sided primary tumor (HR: 3.01; 95% CI: 1.27-7.13; p = 0.017), and BRAF V600E mutation (HR: 4.55; 95% CI: 1.21-17.21; p = 0.025) as independent predictors for worse OS.

CONCLUSION

In addition to confirming the prognostic role of PCI, our study extends the role of BRAF mutation and right primary tumor location as markers for worse prognosis.

Molecular Determinants and Other Factors to Guide Selection of Patients for Hepatic Resection of Metastatic Colorectal Cancer

OPINION STATEMENT

Treatment for metastatic colorectal cancer (CRC) has changed significantly over the last few decades as cytotoxic and targeted chemotherapies have evolved and resection of (technically feasible) colorectal liver metastases (CRLM) has become standard of care for eligible patients. Overall, survival for metastatic CRC has considerably improved, but recurrences are common. Numerous clinical risk scores have been suggested to guide patient selection for CRLM resection, but none perfectly predict outcomes; therefore, a personalized approach to metastatic CRC treatment using genetic profiles for risk stratification and prognostication is a critically important advancement. All patients with suspected metastatic CRC should undergo genetic testing for common oncogene mutations (e.g., KRAS, BRAF, and NRAS) in addition to a triphasic CT scan of the chest, abdomen, and pelvis; if hepatectomy may be entertained and there is concern about the future liver remnant (FLR), liver volumetrics should also be performed. MRI and PET are useful adjuncts for cases in which diagnosis or extent of disease is unclear. The decision to operate should be individualized and based on each patient's condition, tumor biology, and technical resectability. Genetic profiles should be used to inform multidisciplinary meetings surrounding topics of chemotherapy and surgical resection, as well as patient discussions concerning the risks and benefits of surgery. In the end, most patients with technically resectable colorectal cancers and adequate cardiopulmonary fitness benefit from surgical resection, as it remains the only chance of long-term survival.

Effective Strategies to Predict Survival of Colorectal Peritoneal Metastases Patients Eligible for Cytoreductive Surgery and HIPEC

Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC), often combined with systemic therapy, can be offered to selected colorectal peritoneal metastases (PM) patients. However, clinical heterogeneity and the lack of high-level evidence challenges determination of the correct treatment strategy. This review aims to provide an overview of current strategies to predict survival of colorectal PM patients treated with CRS and HIPEC, guiding clinicians to select a suitable treatment-strategy and to inform patients about their prognosis. First, the prognostic relevance of several clinicopathological prognostic factors, such as extent of PM, location of primary tumor, histology type, and the presence of lymph node or liver metastases will be discussed. Subsequently, special attention will be given to recent developments in several aspects of tumor biology such as RAF/RAS mutations, circulating tumor DNA, immunoprofiling, and consensus molecular subtypes. Finally, currently available prognostic models to predict survival will be evaluated, concluding these models perform moderate to good, but most of them partly rely on intra-operative data. New insights in tumor biology, as well as the reliable assessment of extent of peritoneal disease by diffusion weighted MRI pose promising opportunities to establish an adequate and clinically meaningful preoperative prognostic model in the near future.

Twelve-Year Single Center Experience Shows Safe Implementation of Developed Peritoneal Surface Malignancy Treatment Protocols for Gastrointestinal and Gynecological Primary Tumors

Simple Summary

The treatment of peritoneal surface malignancies (PSM) has dramatically evolved during the past two decades. Indications, treatment protocols, surgical techniques and the application of HIPEC in the prophylactic setting were evaluated in the surgical community. Nevertheless, the current results of the PRODIGE-7 trial disfavored the application of HIPEC for PSM of colorectal cancer and raised uncertainty among surgeons. On the other hand, cytoreductive surgery and HIPEC represent state-of-the-art therapy for peritoneal mesothelioma (except the sarcomatoid-subtype) and pseudomyxoma peritonei. Comparing the literature is cumbersome due to the variety of HIPEC protocols and differences in indication settings. This article aims to provide an insight into the impact of different HIPEC protocols, different indication settings and the implementation of pre-HIPEC laparoscopy on patients’ morbidity rates and outcomes and serves as guidance for surgeons dealing with these patients in order to guarantee high-quality treatment.

Abstract

(1) Background: Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy provide survival benefits to selected patients. We aimed to report our experience and the evolution of our peritoneal surface malignancy program. (2) Methods: From June 2005 to June 2017, 399 patients who underwent cytoreductive surgery plus hyperthermic intraperitoneal chemotherapy at the Tübingen University Hospital were analyzed from a prospectively collected database. (3) Results: Peritoneal metastasis from colorectal cancer was the leading indication (group 1: 28%; group 2: 32%). The median PCI was 15.5 (range, 1–39) in group 1 and 11 (range, 1–39) in group 2 (p = 0.002). Regarding the completeness of cytoreduction (CC), a score of 0 was achieved in 63% vs. 69% for group 1 and 2, respectively (p = 0.010). Median overall survival rates for patients in group 1 and 2 for colon cancer, ovarian cancer, gastric cancer and appendix cancer were 34 and 25 months; 45 months and not reached; 30 and 16 months; 39 months and not reached, respectively. The occurrence of grade-III and -IV complications slightly differed between groups (14.5% vs. 15.6%). No 30-day mortality occurred. (4) Conclusions: Specialized centers are able to provide low-morbidity cytoreductive surgery and hyperthermic intraperitoneal chemotherapy without mortality. Strict patient selection during the time period significantly improved CC scores.

Omics analyses in peritoneal metastasis-utility in the management of peritoneal metastases from colorectal cancer and pseudomyxoma peritonei: a narrative review

High-throughput "-omics" analysis may provide a broader and deeper understanding of cancer biology to define prognostic and predictive biomarkers and identify novel therapy targets. In this review we provide an overview of studies where the peritoneal tumor component of peritoneal metastases from colorectal cancer (PM-CRC) and pseudomyxoma peritonei (PMP) were analyzed. Most of the available data was derived from DNA mutation analysis, but a brief review of findings from transcriptomic and protein expression analysis was also performed. Studies reporting genomic analysis of peritoneal tumor samples from 1,779 PM-CRC and 623 PMP cases were identified. The most frequently mutated genes in PM-CRC were KRAS, APC, SMAD4, BRAF, and PIK3CA, while in PMP KRAS, GNAS, FAT4, TGFBR1, TP53 and SMAD3/4 mutations were most commonly identified. Analyses were performed by single-gene analyses and to some extent targeted next-generation sequencing, and a very limited amount of broad explorative data exists. The investigated cohorts were typically small and heterogeneous with respect to the methods used and to the reporting of clinical data. This was even more apparent regarding transcriptomic and protein data, as the low number of cases examined and quality of clinical data would not support firm conclusions. Even for the most frequently mutated genes, the results varied greatly; for instance, KRAS mutations were reported at frequencies between 20-57% in PM-CRC and 38-100% in PMP. Such variation could be caused by random effects in small cohorts, heterogeneity in patient selection, or sensitivity of applied technology. Although a large number of samples have been subjected to analysis, cross-study comparisons are difficult to perform, and combined with small cohorts and varying quality and detail of clinical information, the observed variation precludes useful interpretation in a clinical context. Although omics data in theory could answer questions to aid management decisions in PM-CRC and PMP, the existing data does not presently support clinical implementation. With the necessary technologies being generally available, the main challenge will be to obtain sufficiently large, representative cohorts with adequate clinical data and standardized reporting of results. Importantly, studies where the focus is specifically on peritoneal disease are needed, where the study designs are aligned with clearly defined research questions to allow robust conclusions. Such studies are highly warranted if patients with PM-CRC and PMP are to derive benefit from recent advances in precision cancer medicine.

Systemic therapy in addition to cytoreduction and hyperthermic intraperitoneal chemotherapy for colorectal peritoneal metastases: recent insights from clinical studies and translational research

There is a lack of randomized or high-quality intention-to-treat cohort studies addressing the role of systemic therapy in addition to cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) as part of the treatment of colorectal peritoneal metastases (PM). Therefore, the choice whether or not to treat patients with systemic therapy is currently mainly based on expert opinion. As a result, treatment with neoadjuvant and/or adjuvant systemic therapy is implemented in various ways around the world. The aim of this review was to provide an overview of recent insights with regard to the systemic treatment of PM of colorectal origin obtained from clinical studies and translational research.

Immunohistochemistry features and molecular pathology of appendiceal neoplasms

Primary appendiceal neoplasms (ANs) comprise a heterogeneous group of tumors. The pathology and classification of ANs have been controversial, and thus, a new classification of these neoplasms was published in the World Health Organization (WHO) classification of tumors (5th edition, 2019). However, immunohistochemistry (IHC) features of epithelial ANs are not explained in this edition and the limited data on the molecular pathology of these tumors shows inconsistent findings in various studies. It would be useful to identify biomarkers appropriate for each subtype to better aid in treatment selection. Therefore, we reviewed the literature to investigate what is known of the molecular pathology and IHC features of the most frequently diagnosed pathological subtypes of epithelial ANs based on the recent classification. The inconsistencies in research findings regarding the IHC features and molecular pathology of ANs could be due to differences in the number of samples and their collection and preparation as well as to the lack of a universally accepted classification system for these neoplasms. However, the literature shows that epithelial ANs typically stain positive for MUC2, CK20, and CDX2 and that the expression of SATB2 protein could be used as a biomarker for appendix tumor origin. Low-grade appendiceal mucinous neoplasms tend to have mutations in KRAS and GNAS but are usually wild-type for BRAF, APC, and P53. Conversely, appendiceal adenocarcinomas are frequently found with mutations in KRAS, GNAS, P53, PIK3CA, and APC, and have significant nuclear expression of β-catenin, loss of nuclear or nuclear and cytoplasmic expression of SMAD4, and loss of cytoplasmic membranous expression of E-cadherin. Goblet cell carcinomas (GCCs) typically stain positive for keratin and mucin markers and are frequently mutated in P53 and chromatin-modifier genes, but they tend to be wild-type for KRAS, GNAS, APC, and PIK3CA. The expression of CK7 and SATB2 proteins is usually negative in appendiceal neuroendocrine neoplasms and they lack the mutations in common cancer-associated genes including APC, BRAF, SMAD4, and PIK3C. The available data suggest that GCCs have distinct molecular and immunohistochemical features and that they have characteristics more in common with adenocarcinoma than classical neuroendocrine tumors. In addition, MSI does not seem to have a role in the pathogenesis of epithelial ANs because they are rarely detected in these tumors. Finally, hereditary predisposition may have a role in the development of ANs because heterozygous CTNNβ1, NOTCH1, and NOTCH4 germline mutations have recently been identified in low and high grades ANs.

Pressurized Intraperitoneal Aerosol Chemotherapy for Colorectal Peritoneal Metastases

BACKGROUND

The benefit of repetitive PIPAC specifically in CPM patients has yet to be demonstrated in terms of oncological and functional outcomes.

OBJECTIVE

The aim of this study was to evaluate the outcome of patients with non-resectable colorectal peritoneal metastases (CPM) treated with pressurized intraperitoneal aerosol chemotherapy (PIPAC).

METHODS

We conducted an analysis of a prospective single-center database of all CPM patients who underwent PIPAC with oxaliplatin 92 mg/m² body surface (PIPAC-Ox). The outcome criteria were adverse events (Common Terminology Criteria for Adverse Events version 4.0), Peritoneal Regression Grading Score (PRGS), and survival.

RESULTS

Overall, 102 patients with a median age of 64 years (33-88) were scheduled for PIPAC-Ox. Access to the abdominal cavity for the first application failed in 22/102 (21.6%) patients. A total of 185 PIPACs were performed, with 26/102 (25.5%), 20/102 (19.6%), 17/102 (16.7%), and 17/102 (16.7%) patients undergoing one, two, three, and four or more PIPACs, respectively. Perioperative overall morbidity/mortality Grade I-V occurred in 14 (7.6%), 29 (15.8%), 6 (3.2%), 1 (0.5%), and 1 (0.5%) patient without significant differences between each cycle. Of 27 patients who underwent three or more PIPACs, 20/102 (19.6%) had major/complete CPM regression (PRGS 1-2). In a multivariate analysis, independent predictive factors for > 12 months' survival following the first PIPAC-Ox administration were three or more PIPACs (odds ratio [OR] 4.5, 95% confidence interval [CI] 1.35-15.2; p = 0.014) and younger patient age (OR 1.058, 95% CI 1.00-1.12; p = 0.039).

CONCLUSIONS

Repetitive PIPAC-Ox for CPM patients, alone or combined with perioperative systemic chemotherapy, is feasible. Our data suggest that three or more consecutive PIPAC-Ox cycles for advanced CPM can improve survival.

The role of molecular biomarkers in outcomes and patient selection for cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for peritoneal metastases of colorectal origin

BACKGROUND

Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) is effective in select patients with peritoneal metastases of colorectal (CRC) origin. The impact of different biomarkers in predicting recurrence after CRS/HIPEC is unclear.

METHODS

Retrospective review of patients who underwent CRS/HIPEC for PC of CRC origin from 03/2007-08/2017. Molecular profile of the primary tumor was obtained from pathology reports, whenever available.

RESULTS

Overall, 100 patients underwent CRS/HIPEC for peritoneal metastases of CRC origin. Most patients presented high grade tumor histology (G2/G3, n = 97, 97%), and a majority showed mucinous features (n = 61, 61%). At a median follow-up of 18 months, median DFS for the overall population was 13 months (95% CI 9.6, 16.4). Data reporting at least one mutational analysis was available in 64 patients. Microsatellite stability was detected in 42/50 (84%) patients, mKRAS in 25/51 (49%), and mBRAF in 5/35 (14.3%). On Kaplan-Meier analysis, BRAF was the only mutation associated with poor DFS (16 months, CI 95% 11.7-43.3 vs. 7 months, CI 95% 2.1-11.9, p = .008). On multivariate analysis, mBRAF independently predicted earlier recurrence (p = .032).

CONCLUSIONS

In this analysis, mBRAF was independently associated with earlier recurrence in patients undergoing CRS/HIPEC for CRC, leading to dismal median DFS (7 months). Strict patient selection is advisable in these patients.

Prospective correlation of the radiological, surgical and pathological findings in patients undergoing cytoreductive surgery for colorectal peritoneal metastases: implications for the preoperative estimation of the peritoneal cancer index

AIM

The peritoneal cancer index (PCI) is one of the strongest prognostic factors in patients undergoing cytoreductive surgery (CRS) for colorectal peritoneal metastases. Using pathological evaluation, however, the disease extent differs in a large proportion of patients. Our aim was to study the correlation between the radiological (rPCI), surgical (sPCI) and pathological (pPCI) PCI in order to determine factors affecting the discordance between these indices and their potential therapeutic implications.

METHOD

From July 2018 to December 2019, 128 patients were included in this study. The radiological, pathological and surgical findings were compared. A protocol for pathological evaluation was followed at all centres.

RESULTS

All patients underwent a CT scan and 102 (79.6%) had a peritoneal MRI. The rPCI was the same as the sPCI in 81 (63.2%) patients and the pPCI in 93 (72.6%). Concordance was significantly lower for moderate-volume (sPCI 13-20) and high-volume (sPCI > 20) disease than for low-volume disease (sPCI 0-12) (P < 0.001 for sPCI; P = 0.001 for pPCI). The accuracy of imaging in predicting presence/absence of disease upon pathological evaluation ranged from 63% to 97% in the different regions of the PCI. The pPCI concurred with the sPCI in 86 (68.8%) patients. Of the nine patients with sPCI > 20, the pPCI was less than 20 in six.

CONCLUSION

The rPCI and sPCI both concurred with pPCI in approximately two thirds of patients. Preoperative evaluation should focus on the range in which the sPCI lies and not its absolute value. Radiological evaluation did not overestimate sPCI in any patient with high/moderate-volume disease. The benefit of CRS in patients with a high r/sPCI (> 20) who respond to systemic therapies should be prospectively evaluated.

Clinical and Radiologic Predictors of a Pathologic Complete Response to Neoadjuvant Chemotherapy (NACT) in Patients Undergoing Cytoreductive Surgery for Colorectal Peritoneal Metastases: Results of a Prospective Multi-center Study

BACKGROUND

Patients undergoing cytoreductive surgery for colorectal peritoneal metastases who have a pathologic complete response (pCR) to neoadjuvant chemotherapy experience a significantly longer survival than those with residual disease. This response is known only after surgery. This study aimed to examine clinical and radiologic predictors of a pCR.

METHODS

From July 2018 to December 2019, the study prospectively enrolled 120 patients. The clinical and radiologic findings were compared between patients with and without a pCR. A protocol for pathologic evaluation was followed.

RESULTS

A pCR was observed in 34 patients (28.3%). Receiver operating characteristic (ROC) curves showed that patients with a surgical Peritoneal Cancer Index (sPCI) of 3 or lower had an 80% probability of experiencing a pCR, and that patients with a radiologic PCI (rPCI) of 2 or lower had a 70% probability of experiencing a pCR. A pCR was correctly predicted for 47% of the patients by imaging and for 44.4% of the patients by surgical evaluation. The site of primary tumor, the timing of peritoneal metastasis (PM), histology, tumor marker positivity, and mutations in known poor prognostic genes (KRAS) did not differ between the patients with and those without pCR. The primary tumor showed residual disease in 23.5% and regional nodes in 26.4% of the patients with pCR.

CONCLUSIONS

The rPCI and sPCI concurred with a pCR in less than 50% of the patients. The patients with a lower PCI had greater concordance. An sPCI of 3 or lower was predictive of a pCR in 80% of the patients. The impact of KRAS mutations on pCR should be evaluated in a larger series. The predictors of pCR and response to systemic chemotherapy should be incorporated in prognostic scores used to select patients for surgery.

The role of cytoreductive surgery and hyperthermic intraperitoneal chemotherapy in the treatment of peritoneal carcinomatosis: a systematic review including evidence from Japan

The prognosis of peritoneal carcinomatosis is poor. However, the emergence of cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS + HIPEC) as a treatment option has prolonged survival and it can even potentially cure patients with peritoneal carcinomatosis. Randomized controlled studies and other observational studies indicated that this combined therapy potentially improved the prognosis of patients with colon, gastric, and ovarian cancers with acceptable morbidity and mortality rates. Even in rarer diseases, such as pseudomyxoma peritonei and malignant peritoneal mesothelioma, CRS + HIPEC markedly improved the prognoses over those with conventional treatment. Based on the accumulated evidence, clinical guidelines recommend CRS + HIPEC for selected patients with peritoneal carcinomatosis. However, several issues still need to be overcome. A standard method for HIPEC has not yet been established. Furthermore, the criteria employed for patient selection need to be clarified to achieve real benefits. The peritoneal cancer index, chemo-sensitivity and several biological markers are considered to be key factors.

Prognostic Impact of Primary Side and RAS/RAF Mutations in a Surgical Series of Colorectal Cancer with Peritoneal Metastases

BACKGROUND

Selecting patients with colorectal cancer peritoneal metastases (CRC-PMs) for surgery is still a concern. Biological features have the potential to improve prognostic stratification, but their significance in this clinical setting is still unclear. We assessed the prognostic impact of primary side and KRAS/NRAS/BRAF/PIK3CA mutations in patients treated with either cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) or CRS alone.

METHODS

We reviewed a prospective database of 152 CRC-PM patients selected to undergo perioperative systemic chemotherapy and CRS with or without HIPEC. Extensive mutational analysis of KRAS, NRAS, BRAF, and PIK3CA was performed by polymerase chain reaction (PCR). In 68 patients, Ion Torrent next-generation sequencing technology was used to characterize the hotspot regions of 50 genes.

RESULTS

The primary tumor was right-sided in 61 patients (40.1%) and left-sided in 91 patients (59.9%). Right-sided primaries were associated with mutated KRAS (p = 0.01) and normal carcinoembryonic antigen (CEA; p = 0.03). KRAS was mutated in 71/152 patients (46.7%), NRAS in 7/152 patients (4.6%), BRAF in 10/152 patients (6.6%), PIK3CA in 17/78 patients (25.0%), TP53 in 37/68 patients (54.4%), APC in 25/68 patients (36.7%), SMAD4 in 13/68 patients (19.1%), and FBXW7 in 5/68 patients (7.4%). Median follow-up was 54.9 months and median survival from PM diagnosis was 45.1 months. The right-sided primary (hazard ratio [HR] 1.62, 95% confidence interval [CI] 0.43-0.89; p = 0.011), BRAF mutations (HR 2.21, 95% CI 1.05-4.63; p = 0.038), and Peritoneal Cancer Index (HR 1.47, 95% CI 1.03-2.10; p = 0.036) independently correlated with poorer survival, while APC mutations univariately correlated with better survival (p = 0.03).

CONCLUSIONS

BRAF mutations and right-sided primary are adverse prognostic factors that may be used to optimize therapeutic strategies. APC may be involved in CRC-PM development and progression.

A population-based study on the prognostic impact of primary tumor sidedness in patients with peritoneal metastases from colon cancer

Primary tumor location is an established prognostic factor in patients with (metastatic) colon cancer. Colon tumors can be divided into left‐sided and right‐sided tumors. The aim of this study was to determine the impact of primary tumor location on treatment and overall survival (OS) in patients with peritoneal metastases (PM) from colon cancer. This study is a retrospective, population‐based cohort study. Records of patients diagnosed with colon cancer and synchronous PM, from 1995 through 2016, were retrieved from the Netherlands Cancer Registry (NCR). Data on diagnosis, staging, and treatment were extracted from the medical records by specifically trained NCR personnel. Information on survival status was updated annually using a computerized link with the national civil registry. In total, 7930 patients were included in this study; 4555 (57.4%) had a right‐sided and 3375 (42.6%) had a left‐sided primary tumor. In multivariable analysis right‐sided primary tumor was associated with worse OS (HR: 1.11, 95% CI 1.03‐1.19, P = .007). Of all patients diagnosed with PM, 564 (7.1%) underwent cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS‐HIPEC). Patients with left‐sided primary tumors were more often candidates for CRS‐HIPEC (6.5% vs. 8.0%, P = .008). OS of patients with right‐ and left‐sided tumors who underwent CRS‐HIPEC did not significantly differ. In conclusion, primary right‐sided colon cancer was an independent prognostic factor for decreased OS in patients diagnosed with synchronous PM. In patients treated with CRS‐HIPEC location of the primary tumor did not influence survival.

Histology and its prognostic effect on KRAS-mutated colorectal carcinomas in Korea

KRAS mutation is frequently identified in advanced colorectal carcinoma (CRC); however, its prognostic significance and the associated histological features have remained to be clarified. In the present study, the precise histological results and prognostic value of KRAS-mutated CRCs were investigated in patients from South Korea. A retrospective review of the results from KRAS mutation testing, as well as evaluation of the histology of 310 cases of CRC at various stages, were performed. Cross-tabulation and survival analysis were performed according to the KRAS status. Patients with KRAS mutation more frequently exhibited serrated and papillary architectures (P=0.009 and P=0.014, respectively). KRAS mutation was an independent unfavorable prognostic factor for overall survival (OS) according to multivariate analysis (P=0.001), whereas no association was observed with disease-free survival (DFS) (P=0.611). Of note, in the subgroup of KRAS-mutated carcinomas, the presence of a solid component on histology was associated with less favorable OS (P=0.032). Furthermore, among the wild type cases, patients with a micropapillary component had a worse OS than those who did not (P=0.018). However, no subgroup or specific histological features were associated with DFS. In summary, KRAS-mutated CRCs had a moderate association with particular histological features, and according to the KRAS mutational status, there was a certain degree of association between histology and prognosis.

Identification of pharmacogenetic biomarkers for efficacy of cytoreductive surgery plus hyperthermic intraperitoneal mitomycin C in patients with colorectal peritoneal metastases

INTRODUCTION

Mitomycin C (MMC) is commonly used in patients with colorectal peritoneal metastases (CPM) treated with cytoreductive surgery plus hyperthermic intraperitoneal chemotherapy (CRS + HIPEC). MMC requires metabolic activation prior to exert its cytotoxic effect of which the main activating enzymes are NQO1 and POR. However, not all patients are able to activate MMC for example due to polymorphisms in the genes encoding these enzymes. The aim of this study was to investigate the association of NQO1∗2, NQO1∗3, and POR∗28 with the efficacy of CRS + HIPEC with MMC in patients with CPM.

METHOD

A retrospective follow-up design was used to study genetic association in patients with histologically proven CPM treated with CRS + HIPEC with MMC with respect to peritoneal recurrence rate after 3 months (primary endpoint), after 6 months, disease-free survival and overall survival. Genetic polymorphisms NQO1∗2, NQO1∗3, and POR∗28 were tested for association.

RESULTS

A total of 253 patients were included. In NQO1∗3 carriers the peritoneal recurrence rate 3 and 6 months after HIPEC was significantly higher than in wild type patients, respectively 30.0% vs 3.8% (p = 0.009) and 40.0% vs 12.1% (p = 0.031). In line with these results, NQO1∗3 was associated with a shorter disease-free survival (HR 2.04, 95% CI [1.03-4.03]). There was no significant association with overall survival (HR 1.42, 95% CI [0.66-3.07]).

CONCLUSION

Carriership of the NQO1∗3 allele is associated with worse peritoneal recurrence rate and disease-free survival. These results suggest that individualization of patients treated with CRS + HIPEC based upon pharmacogenetics may be beneficial.